With imaging technology of mobile terminals continually developing, more and more mobile terminals use a dual camera for photography. This is because by combining different cameras to perform dual-camera imaging, photograph qualities or depth of field detection may be enhanced, thereby achieving better photography effects.
When cameras shoot a to-be-photographed object, the dual camera needs to determine a focal length at which clear imaging can be accomplished, to shoot the to-be-photographed object at the focal length. However, in the related art, a time period from an instance when the dual camera begins focusing to an instance when the focal length at which clear imaging can be accomplished is determined is too long—that is, focusing speed is slower. In the related art, the slower focusing speed of the dual camera is disadvantageous to users performing snap shooting, and results in difficulties in capturing instant pictures.